Underwater production satellite

ABSTRACT

This specification discloses a method and apparatus for the production of subaqueous deposits of fluid minerals through a subsea satellite system. The wells are drilled in a circular pattern through a template on the marine bottom serving also as base upon which the satellite body is installed. The production and control passages of each of the wells are connected to production equipment within the satellite body by separate connector units, independently lowered into place from a surface vessel, to form portions of fluid paths between the passages within the subsea wellheads and the production equipment within the shell of the satellite. Such an installation permits production through the satellite, installed on the template base, after only one of the wells has been drilled and completed. The produced fluids are separated and/or metered within the satellite prior to being transported to storage. Flowline tools are programmed to enter the various subaqueous wells through the connector units. Hydraulic circuitry and controls are provided for pumping the tools and chemicals down through the various wells and for retrieving the tools. Also disclosed is a hot water well utilized in conjunction with the heat exchanger within the satellite for warming the separated-off gases to prevent the formation of hydrates.

United States Patent [72] Inventors William A. Talley,Jr.

Dallas, Tex.; James T. Dean, Dallas, Tex. [21] Appl. No. 740,783 [22]Filed June 27, 1968 [45] Patented Jan. 19, 1971 [7 31 Assignee Mobil OilCorporation a corporation of New York [54] UNDERWATER PRODUCTIONSATELLITE 33 Claims, 8 Drawing Figs.

[52] US. Cl 166/265, l66/.5 [51] Int. Cl E2lb 39/00, E2 1 b 33/035 [50]Field of Search 166/265, 267, 5.6, 265, 315, 154

[56] References Cited UNITED STATES PATENTS 2,810,442 10/1957 Tausch166/315X 3,366,173 l/1968 Mclntosh l66/.5 3,373,806 3/1968 Stone 166/.53,381,753 5/1968 Fredd 166/154X 3,396,789 8/1968 Dean 166/.5 3,422,8951/1969 Koonce 166/79 3,444,927 5/1969 Childers et al.

Primary Examiner-Marvin A. Champion Assistant ExaminerRichard E. FavreauAttorneysWilliam J. Scherback, Frederick E. Dumoulin,

Alan G. Paul, Donald L. Dickerson and Sidney A. Johnson ABSTRACT: Thisspecification discloses a method and apparatus for the production ofsubaqueous deposits of fluid minerals through a subsea satellite system.The wells are drilled in a circular pattern through a template on themarine bottom serving also as base upon which the satellite body isinstalled. The production and control passages of each of the wells areconnected to production equipment within the satellite body by separateconnector units, independently lowered into place from a surface vessel,to form portions of fluid paths between the passages within the subseawellheads and the production equipment within the shell of thesatellite. Such an installation permits production through thesatellite, installed on the template base, after only one of the wellshas been drilled and completed. The produced fluids are separated and/ormetered within the satellite prior to being transported to storage. Flowline tools are programmed to enter the various subaqueous wellsthrough the connector units. Hydraulic circuitry and controls areprovided for pumping the tools and chemicals down through the variouswells and for retrieving the tools. Also disclosed is a hot water wellutilized in conjunction with the heat exchanger within the satellite forwarming the separated-off gases to prevent the formation of hydrates.

PATENTEUJAN 19 I97! SHEET 1 BF 6 INVENTOR J AMES T. DEAN WILLIAM A.TALLEY,JR

azwg/ aal ATTORNEY 'PATEN EDJAMQIQII I 3.556218 SHEET 2 (IF 6 INVENTORJAMES 1'. DEAN WILLIAM A. TALLEY, JR.

ATTORNEY PATENTEU mu 9m SHEET 3 BF 6 INVENTOR JAMES T. DEAN WILLIAM A.TALLEY; JR,

ATTORNEY P \TENTED JAN 1 9 IBYI T0 WELL 8 WELLHEAD EQUIPMENT T0 MARINEBOT TOM "m mic SHEET 5 OF 6 FIG. 6

H d SUPPLY SYSTEM :34 -Qm FLARE CLEAN, DEAD on. SUPPLY FOR TFL FLUID TOSTORAGE M/ZZZ TO STORAGE OR EAD 'OIL SUPPLY FOR TLF FLUID) SUPPLY SYSTEMTO STORAGE INVENTOR JAMES T. DEAN WILLIAM A. TALLEY, JR.

ATTORNEY PATENIED JAN 1 9 I97;

sumsnse JAMES T. DEAN WILLlAM A. TALLEY, JR,

azmmwp ATTORNEY BACKGROUND OF THE INVENTION l. Field ofthe Invention jThis invention relates to a subsea satellite designed to beinterconnected with a group of subaqueous' wells having subsea wellheadsso as to control the productiontherefrom and to provide ordinarymaintenance therefor. More particularly, the invention relates to asystem for inserting one or more types of tools, and/or chemicals, downthrough selected wells and for retrieving the tools 'upon thecompletion'of the respective function.

2. Description of the Prior Art Since its inception, the offshore oiland gas industry has used bottom-supportedabove-surface platforms as theprincipal mechanism for the installation and support of the equipmentand services necessary for the production of the subaqueous mineraldeposits. As the industry has developed over the years, it has extendedits search for offshore minerals from its birthplace, producing oil andgas in theshallow coastal waters off California and the Gulf of Mexicointo areas where, because of excessive water depth and/orother localconditions, the bottom-supported platform is not as economically ortechnologically feasible.

While theoretically there is no limit to the depth for which abottom-supported platform can be designed and installed, experience todate indicates that platform costs increase almost exponentially withthe increase in water" depth. Thus, the presently estimated costs of aplatform to carry the production facilities for a field in 400 feet ofwater or more are so high as to indicate that such an installationcannot be justified economically for any but the most productivefields.Furthermore, the few bottom-supported above-surface platforms that havebeen designed and built for use in 300 feet or more of water depth havealmost invariably suffered-leg failures of one type or another.

A possible solution is to install the production facilities on afloating platform, as is described in the H/D: Cox Pat. No. 3,111,692,issued Nov. 26, I963, which can be maintained in position in a field byeither a fixed multipoint mooring system of anchors and anchor lines, orby adynamic positioning system. The above solution involves theexpense'of continuous maintenanceand surveillance of the locating;system as well as the associatedproblems and expense of maintaining themultiple flexible lines connecting wellheads on the marine bottom withthe continuously moving floating production platform, and the potentialhazard, of this system to, the hoses, in the event of a failure of thefixed mooring or dynamic positioning systems.

Another consideration is that, in many areas of the world, localconditions other than water depth impose critical limitations on the useof bottom-supported production platforms. In arctic areas, abottom-supported platform must be built to withstand the forces imposedby ice that forms on the water surface during the winter months of theyearQand in many such areas all year long; Furthermore, any above-waterproduction platform is subject to the mercyofthe wind and waves,especially those occurring during hurricanes and other violent storms.In the arctic areas these storms can be exceeded by the forces exertedagainst the platform by movement of the thick ice layers that freeze onthe surface of the water. Forexample. in Cook Inlet, Alaska, the localextremely high tidal movementson' the order of 30 feet or more causevery fast tidal currents in the Inlet, with velocities of up'to8 tomiles an hour 'or more. These very rapid currents carry with themtheheavy pack ice that forms on the surface of the Inlet,

so that it bearswith tremendous force against any fixed structure, suchas a production platform, that should be installed in its-path. 1-

In-still other areas it is not adverse natural,: but manmade, conditionsthat restrict the use of bottom-supported abovesurface productionplatforms. Among such conditions could be listed official and/or publicobjection to oil production facilities near public recreational orresidential areas, and the presence of heavy-marine traffic as inharbors, channels, rivers, and other navigatable bodies of water whichmake it necessarily advantageous to install as much of the productionequipment beneath the water surface as possible. For example, the firstknown use of subsea wellheads is in Lake Erie I where gas is producedfrom subaqueous formations beneath the heavily traveled lake.

Therefore, it would appear that where there is extremely deep waterand/or adverse surface conditions, a fully subsea installation would bethe most advisable solution. One method, as is shown by the J. A. HaeberPat. No. 3,261,398, issued Jul. 19, 1966, is to locate the individualpieces of production equipment on the marine bottom. Such aninstallation almost necessitates the use of robots such as shown in theG. D. Johnson Pat. No. 3,099,3 l6, issued Jul. 30, 1963. However, suchinstrumentalities are expensive and not without their own limitationsand maintenance problems. Another solution is suggested by the H. L.Shatto, Jr. et al. Pat. No. 3,221,8l6, issued Dec. 7, I965, wherein theproduction equipment for a plurality of wells is grouped within asatellite chamber adapted to' be raised to the surface for repair and/ormaintenance.

To economically package production equipment used for scheduling,measuring, separating, and otherwise performing the usual manipulationson producing oil and gas wells, it is believed to be necessary toenclose the equipment within a pressure-resistant satellite shell withinwhich can be maintained a breathable atmosphere permitting the equipmentin side to be serviced and/or maintained by personnel, not encumberedwith diving suits. Single well chambers, most being removable, have beenproposed and are exemplified by the J. D. Watts et al. Pat. No.3,202,216 issued Aug. 24, I965. The

most feasible system should include a subsea satellite havingtherewithin production equipment servicing a number of wells and capableof maintaining life sustaining conditions therewithin.

No feasible system has been presented. to date for economicallymaintaining the several serviced wells in operating condition duringproduction. This would require the periodic passing through of tools forcutting paraffin, setting chokes, removing sand, and other operationsnormally done with wirelines in a land or platform-supported well. Anecessary part of such a maintenance system is means for detecting amalfunction in a well or in simpler installations, for instance, wherefrequent paraffin cutting is necessary, a timed sequence can be used.Apparatus must be provided for moving a single tool selectively throughone of a number of wells and for storing one tool when one performing adifferent function is to be directed into a well.

While wireline tools have been used for many years to maintain wells andthrough-the-flowline (TFL) tools are known and have been used at leastexperimentally, a complete automatic system for maintaining severalwells as a group is not available. The P. R. McStravick et al. Pat. No.3,022,822 discloses a system for pumping a wireline tool down through asingle subsea wellhead from a nearby above-surface location, but is notconcerned with the selection of a particular tool, the timing of theoperation, or the storage of the tool for a second operation. The F. H.Culver et al. Pat. No. 3,l0l,l l8 discloses a subsea wellhead to beutilized in conjunction with a wireline tool which is guided in and outof the wellhead through wide branch conduits thereof. The S. A. Bergmanet al. Pat. Nos. 3,063,079 and 3,063,080 disclose launching devices forinserting pipe scraping tools or pigsinto a pipeline while the K. D;Savage Pat. No. 2,856,884 discloses a system for storing a pig in anadjacent pipe when it is not being used in the pipeline.

SUMMARY OF THE INVENTION In accordance with this invention, fluidproduced from a plurality of wells, through subsea wellheads, isprocessed within a satellite station prior to being transported tostorage. The produced fluid from the plurality of wells is combined intoa single stream within the satellite station. The fluid stream is chokedto reduce the wellhead pressure to that necessary to drive the fluid upto a surface installation. The fluid is then directed into a pluralityof gravity separators connected in parallel. The gas taken off from theplurality separators is recombined and the main portion thereof directedto storage, utilized in a gas lift operation, or disposed of by flowingor being injected into shallow sand formations. A minor portion of thegas may be utilized to drive a turbine of a turbine-pump for pressuringup a TFL (through-the-flowline) system. The liquids, including oil andgas and sediment, are directed through the lower ends of each of theseparators, the liquids being recombined and transmitted to storage. Aclean oil pickup from within at least one of the separators directed oilfrom a point above the sediment level of the respective separator to thepump portion of the TFL system. In a storage tank forming alower portionof the satellite body, open to the sea at the lower end thereof, a welltreating fluid may be stored. Alternatively, the well treating fluid canbe stored in and supplied from a surface vessel moored over the site.Wherever the source of treating fluid, it is in fluid communication witha first inlet of the turbine-pump through a three-way two-positionvalve, the second inlet thereof being connected to the clean oil sourcewhereby a prescribed amount of treating fluid followed by clean oil canbe pumped into the TFL circuitry behind a tool whereby the TFL tool isforced through the subsea wellhead and down into the respective well toperform a desired function. In place of the turbine-pump, anelectrically driven pump may be used. In this case, the clean oil pickupline is dispensed with. Where a medium or high GOR (gas-to-oil ratio) isencountered, a heat exchanger unit is necessary to prevent hydrateformation, minimize excessive paraffin deposition, and restrict emulsionformation. For a medium GOR, the unit may consist of only passing thefluid prior to expansion in close conjunction with the fluid afterexpansion within an insulated area. Where there is a high GOR, anoutside heat source is necessary.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a pictorial view of a subseaproduction system in accordance with the present invention;

FIG. 2 is a'partially broken away enlarged view of one of the satellitestations shown in FIG. 1, illustrating the arrangement of the equipmenttherewithin;

FIG. 3 is a schematic representation of a heat exchange system to beutilized within the satellite station also, but shown in less detail inFIG. 2;

FIG. 4 is a schematic diagram of the basic circuitry required to producea plurality of oil and gas wells within a satellite station;

FIG. 5 is a schematic diagram of a modified TFL Fluid Supply System;

FIG. 6 is a schematic diagram of a modified production system forproducing a field having a high gas-oil ratio;

FIG. 7 is a schematic diagram of a modified production system forproducing a field having a medium gas-oil ratio; and

FIG. 8 is a schematic diagram of a modified satellite stationconfiguration for allowing the satellite body to be installed on a basetemplate of a satellite station prior to the completion of any of thewells through the base template.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Now looking to FIG. 1, a subseasystem for producing fluid minerals, in particular gas and oil, from asubaqueous field by a plurality of subsea wellheads is illustrated. Aplurality of subsea production satellite stations, generally designated10, are spaced across a marine bottom 12, each satellite station 10comprising a satellite body centrally positioned within a circular groupof closely spaced subsea wellheads 14. The

produced fluids from the subaqueous wells are directed throughencircling subsea wellheads 14 into the satellite body 15 of therespective satellite station 10. The fluids being produced from thesubsea wellheads 14 of each circular group are combined within therespective enclosed satellite body 15 and a first stage of separation(gravity) takes place. At least the liquid portion is then directed to acircular manifold 16 atop a central bottom-mounted storage tank 17through a shipping line 18, one shipping line 18 extending from eachsatellite station 10.

A floating master station 20, having power generating and final stageseparation equipment thereon, as well as being fitted out withoff-loading apparatus, is in fluid and electrical communication with thebottom-supported storage tank 17 through a tensioned tether pipe 22extending from the storage tank 17 to a point just beneath the turbulentsurface zone of the body of water and fixed at this point to a largesubsurface buoy 24. A flexible conduit 26, containing a plurality ofelectrical and fluid flow paths, extends from the upper end of thetensioned tether pipe 22 to the floating master station 20. The producedliquid, collected in the circular manifold 16, is directed to the masterstation through a main shipping line 27 supported along the length ofthe tether pipe 22, and a fluid line forming a portion of the flexibleconduit 26. The produced liquid passes through the final stageseparation equipment on the master station 20 where the pressure isnormalized and dissolved gases are removed. The dead liquid is thentransported to storage within the storage tank 17 through a line of theflexible conduit 26 connected to an axial passage in the interior of thetether pipe 22.

In the upper left-hand corner of FIG. 1 is illustrated the drilling of awell through a satellite base template, generally designated 28, whichhas been previously installed on a marine bottom along with a shippingline 18' for connecting a satellite station, when completed inconjunction with the template 28, with the storage tank 17. A drillstring 30 is suspended from above the surface from a semisubmersibledrilling vessel 32 and extends through a blowout preventer stack 33mounted on one of a plurality of upstanding well conductor pipes 34forming a portion of the template 28. Illustrated in the lower portionof FIG. 1 is a manned submersible work vehicle, generally designated 36,of a type to be employed at assist in the subsea operations and for thedry transfer of personnel to the satellite station 10. The submersiblework vehicle 36 has a pair of articulated arms 38 and 40 carrying asocket wrench 42 and a vise grip tool 44, respectively. The submersiblework vehicle 36 is further equipped with a pivotable positioning motor46 on each side (one shown) to assist in locating the submersible workvehicle 36 adjacent a satellite station 10 firstly when subseaoperations are to be performed during the drilling operations and theinstallation of the satellite body 15 therewithin, and at later timesduring maintenance and workover operations. A lower port 48 of thesubmersible work vehicle 36 is connected with a rear compartment (notshown) within the shell thereof to permit a diver to be released at aninstallation site if one should be needed. The rear compartment isisolated from the pilots compartment, seen through the front view plate50, so that a diver after exposure to deep water can be kept incompression in the rear compartment while the front compartment ismaintained at atmospheric conditions. This general type of submersiblework vehicle is well known in the artand specific vehicles of this typeare more fully described in the application Ser. No. 649,959, filed Jun.29, 1967, of Warren B. Brooks, Charles Ovid Baker, and Eugene L. Jones,and the references cited therein.

Now looking at FIG. 2, the interior of the satellite body 15, as well asthe satellite base template 28, are illustrated in more detail. Theinternal equipment comprises that necessary for a high gas-oil ratio,high pressure field. The base template 28 comprises an outer ring 51 towhich are rigidly connected the plurality of upstanding vertical wellconductor pipes 34 through which subaqueous wells have been drilled. Asshown, I

a dual completion wellhead 14 is mounted on the upper end of each of thewell conductor pipes 34 in completing each of the respective subaqueouswells. The satellite body is installed after the completion of all ofthe wells drilled through the respective base template 28. The satellitebody 15 is shown to be cradled in a plurality of radially extendingspaced arms 41 fixed to the base template 28. Threaded detent rods 43extend through each of the arms 41 and through the shell of thesatellite body 15 into receivers 45 fixed to the inner wall of theshell. The detent rods can be screwed into and out of engagement withthe receivers by means of the socket wrench 42 of the submersible workvehicle 36. A hex nut 53, terminating in a conical guide, is affixed tothe outer endofeach detent rod 43. Support frames 47, having pillowboxes 49 in which the detent rods 43 are journaled, allow the use oflong detent rods 43 extending radially out beyond the well conductorpipes 34.

A water well 52 is shown as having been drilled through the center ofthe base template 28 and is necessarily completed prior to theinstallation of the satellite body 15. After all of the wells, includingthe water well 52, have been completed, the satellite body 15 is loweredinto place and is leveled and locked into the base template 28 in anysuitable manner. There would be no reason why one water well could notbe drilled through one of the well conductor pipes 34 on the ring 51 ofthe base template 28, if this should prove more convenient. The onlydisadvantage would be the elimination of one possible producing well.The W. F. Manning patent applications Ser. Nos. 663,799 and 663,798entitled Subsea Satellite Foundation Unit and Method for Installing aSatellite Body Within said Foundation Unit, and Subsea Satellite Foundation Unit and Method for Installing a' Satellite Body Therewithin,respectively, disclose alternate leveling and locking nieans as well asmeans for registering the installed satellite with respect to encirclingwellheads.

The water well 52 is designed to providea heat source for a heatexchanger unit (to be discussed below)to warm the produced fluids aftera pressure cut has been taken. The well water may also be directedthrough radiators in the portions of the satellite body 15 in whichpersonnel are present to raise the interior temperature of that portionof the satellite body 15 above the ambient temperature at the marinebottom. In deep water the temperature at the marine bottom isin therange of 35 F. to 45 F., too cold for a man towork. for long periodsunless he is heavily clothed.

Each of the submerged dual completion wellheads 14 has a pair ofupstanding tubing nipples (not shown), each being in fluid communicationwith a producing zone. Each of the pairs of tubing nipples is adapted totelescope into complementary passages of stabover connector unit,generally designated 54, comprising a pair of downwardly curving tubingsections 56 extending radially outward from within the shell ofsatellite body 15 and terminating in vertical lubricator sections 58. By

means of the stabover connector units 54, the production and controlpassages extending through the subaqueous wells are connected tomanifolds within the satellite body 15 for the combining of the producedfluids through the satellite body 15 and/or for the injection of liftgas, or other fluids utilized in secondary recovery procedures, from thesatellite body 15, to allor selected ones of the subaqueous wells; Asshown in the embodiment of FIG. 2, the stabover connector units 54 arepermanently fixed with respect to the satellitebody 15. Therefore, thesatellite body 15 must be radially positioned quite precisely so thatthe stabover connector units 54 can register with and telescope over theupstanding tubing nipples of the respective wellheads l4. 1

An escape hatch 60 is formed within the upper end of the satellite body15 to permit the entry of an operator 62 from a diving bell or travelchamber, as shown in the Townsend application Ser. No. 521,745, filedJan. 19, 1966, ora submersible work vehicle 38. The upper portion of theinterior of the satellite body 15, within which the operator 62 is shownsitting at a panel 64, comprises a control section, generally designated66, from which various operations, not normally programmed,

may be controlled and from which stored information can be retrieved.Below the control section 66 is a production section, generallydesignated 68, containing the various equipment necessary to separateand meter the produced fluids as I 5 well as to pump treating fluids andtools through the various I in one or more operations. Although someplumbing extends through the storage section 70, it is substantiallyuncluttered to permit the storage of a large quantity of well treatingfluid.

Centrally located, within the production. section 68, is a cylindricalheat exchanger unit 74. Equiangularly spaced around the heat exchangerunit 74 are a plurality of spherical separators 72. The produced fluidsnormally flow through the shell of the satellite body 15 by way of thetubing section 56 of the connector units 54. From a tubing section 56the fluid is directed by a branch conduit 76 through an expansion valve(shown in FIG. 3 and to be discussed with respect thereto) into an upperheat exchanger manifold 78 located within the upper end of an insulatedjacket 79 of the heat exchanger unit 74. Fluids, exiting from themanifold 78, flow down through a central pipe 80, leaving the heatexchanger unit 74 near the lower end thereof by means of conduits 82(one shown) which lead the produced fluids into the individualseparators 72.

The separators 72 in the satellite station 10 are of the gravity type topermit the separation of the gas from the oil without a substantialtemperature drop in the separators, avoiding hydrate and paraffindeposition problems therewithin. A loss of 7 F. to 8 F. would be normalwith such equipment. With a one-minute retention time within theseparator, all of the free gas will be removed, only the gas, dissolvedin the liquid at the separator pressure, remaining for the secondary, orfinal,

separation stage. While the separators planned for this installationhave no water knockout feature, provision for removal of water from theoil could be provided if it was desirable at this stage of production.The pressure at which the separators 72 are designed to function may begoverned by the depth at which the satellite station 10 is located sinceit is desirable to have sufficient pressure to lift the oil from themarine bottom to the master station 20 on the surface. [in very deepwater the produced oil may have to be lifted, at least in part, bypowerdriven pumps. Where the satellite is connected into a truckpipeline, rather than being transported away by tanker, the outputpressure of the separators would be governed by the line pressure in thepipeline. Where the wells are producing with a wellhead pressure of, forexample, 1,500 p.s.i. and the 5 satellite station 10 is located in 2,000feet of water, a 900- pound pressure drop will be taken, prior tointroducing the produced fluid into the separators 72, to obtain apressure of approximately 600 p.s.i., which would be that'necessary todrive the oil from the marine bottom to the surface.

Taking a pressure drop of 900 p.s.i. lowers the temperature of theproduced fluids by more than 50 F. When considering a 10,000-foot wellin which the produced fluids at the wellhead would be at from F. to F.,at 50 F. the resultant temperature would be well within the formationtem- 5 perature of hydrates and paraffms.

70 a heat source to increase the temperature: of the mixed oil and gason the downstream side of the choke 84 where a pressure out has beentaken, to prevent hydrate formation, minimize excessive paraffindeposition in the equipment, and restrict emulsion formation. The heatexchanger unit 74 depends 5 upon well water obtained from the previouslymentioned water well 52 (shown only in FIG. 2). The water is producedthrough a normal type of oil well completion and then flows through avariable choke 86 that regulates the flow and downstream pressure. In anexample, using a 10,000-foot water well, the water at the upper end ofthe heat exchanger will also be in the range of 150 F. to 170 F. Thewater from the well 52 is directed upward through a conduit 88, enteringthe insulated cylindrical jacket at 79 of the heat exchanger unit 74,through the upper end thereof. The water travels down through theinterior of the heat exchanger jacket 79, emerging from the lower endthereof in outlet line 90 from which the water is dumped into the sea.As the cold produced fluid passesinto the manifold 78 within the upperend of the heat exchanger unit 74, after passing through the expansionchoke 84 and a one-way valve 92, the fluid comes into indirect contactwith the warmer water flowing around the manifold 78. From the manifold78, the produced fluid flows through a helical coil 94 extending axiallythrough the heat exchanger unit 74 and into a'heat exchanger manifold(not shown) in the lower end thereof, and then out of the jacket 79through conduits 82, each connected between one of the separators 72 andthe lower heat exchanger manifold. A temperature sensor 96 is installedin at least one of the outlet lines 82 to act as a flow indicator andmonitor mechanism to control the increase or decrease of the waterflowing into the heat exchanger unit 74. By increasing or decreasing thesize of the choke 80, the water flow is regulated to maintain therequired temperature of the produced fluids entering the separators 72(FIG. 2). Such a system also acts as a resource conservation in thatlarge use of produced oil and/or gas to fire such heater equipment aswould be otherwise needed is not required.

Looking back to FIG. 2, the liquids leave the separators 72 throughrespective liquid outlet lines 98, connecting the separators 72 withliquid output manifold 100 centrally positioned around the lower end ofthe heat exchanger unit 74. The combined produced liquid from theplurality of separators 72 is directed from the manifold 100 through amain oil outlet line 102 which is connected to the input end of arespective shipping line 18.

The liquid is removed, at the lower end of each of the separators 72, bythe respective line 98 so as to also drain off all the water, entrainedsand, and other impurities with the oil. These impurities mightotherwise impede the action of the separator 72 and cause a prematuremalfunction thereof. A shutoff valve 104 in each of the liquid outletlines 98 is controlled in conjunction with a float (not shown) withineach of the separators 72, to regulate the levels of the liquid withinthe separators 72. As shown, a mechanical linkage is utilized betweenthe float and the valve 104. One of the electromechanical systems, wellknown in the art, could be substituted for the mechanical linkage. Aclean oil line 108 is con nected at a first end thereof into at leastone of the separators 72, above the lower end thereof, to pick up oilfrom above the sediment level and below the low level of the liquid toprovide substantially clean oil (with dissolved gas) for pumping a toolinto and down through a selected well. Line 108, at the other endthereof, is connected to a first inlet of three-way two-position valve110, the outlet of which is connected to the inlet of a gas-driventurbine-pump 112 to provide the clean oil under pressure to the TFLsystem. A second inlet of the three-way two-position valve 110 is alsoconnected to a line 114 having a pickup head 1 16 in the fluid storagesection 70 of the satellite body to provide a source of treating fluidfor the turbinepump 112. Gas under pressure, for driving the turbineportion of the turbine-pump 112, is provided through a turbine gassupply line 118 extending from an auxiliary turbine (not shown in thisview) which is supplied with produced fluid tapped off, through lines 1l9, upstream of the chokes 84. The clean oil under pressure from thepump portion of the turbinepump 112 is fed into a manifold (not shown inthis view). From this last-mentioned manifold, the oil is pumped out,being selectively directed into one or more pressure lines 122, eachpressure line 122 being connected into a bypass conduit section 124 justbehind a TFL tool 126 stored therein. Each bypass conduit 124 isdirectly connected to a curved tubing portion 56 of a connector unit 54for pumping the TFL tool 126 therein into the connected wellhead 14 anddown a passage of the respective well. The separated-out gas, leaving aseparator 72 through an upper pipe or gas outlet line 120, is combinedwith the separated-out gas from the other separators 72 in a ringmanifold unit 128 encircling the insulated jacket 79 of the heatexchanger unit 74.

The separated-out gas can be, in various instances, utilized inproduction procedures, stored for eventual transportation to shore, ordisposed of at the site of the offshore production field. A main outletline 130, from the ring manifold 128, is shown directing the gas out ofthe satellite station 10 for disposal through one or more distant gasdisposal wells (not shown) where the gas will be injected into shallowsands underlying the marine bottom. A safety regulator valve 132 isconnected in the main outlet line to allow gas to be bled off through aflare line 134 to the master floating station 20, if the pressure in themain outlet line 130 should rise above a predetermined value. If the gasobtained in the primary stage of separation is to be either disposed ofby flaring or is to be stored for future transportion-to-shorefacilities, it is conducted to the master station 20 by shipping line(not shown), as described with respect to the produced oil. At themaster station 20, the gas obtained from the primary stage of separationis combined with the gas obtained from the secondary or final stage ofseparation on the master station 20. If the gas is to be flared, a flarestack is erected above the master station 20. If the gas is to bestored, it is first compressed at the master station 20 and then ispumped down to a portion of the storage tank 17 or to a separate storagetank (not shown) nearby. As noted above, the gas from the primaryseparation stage may also be utilized in production procedures, the mostcommon of these procedures being the utilization of the gas underpressure to provide lift pressure in the producing formations. A gasinjection well for this purpose may be one of the wells drilled throughthe ring 51 of the template 28, in which case a separated-out gas is fedinto the wellhead 14 through a respective one of the curved tubingsections 56 of a stabover connector unit 54, or the injection well maybe located at a distance from the satellite station 10, in which case aninterconnecting flowline having a pressure regulator valve and a flareline, as described above with respect to injecting the gas into shallowsand formations, will be utilized.

FIG. 4 illustrates, in schematic form, a complete system, with theexception of a storage means, for the production of a low gas-oil ratiolow pressure field. The fluid is produced in the portion of the systemdesignated as Well and Wellhead Equipment at the TD (total depth) 136 ofa representative well, generally designated 138. In the well 138 is astorm choke 140 placed at approximately a 3,000-foot depth, below thenormal lower limit of paraffin deposition, for safety purposes.Quarter-turned manually operated valves 142 are mounted on the wellhead14 outside the satellite body 15 where they are easily accessible foroperation by a man, robot, or a manned craft such as the underwatersubmersible work vehicle 36 illustrated in FIG. 1. In some instances, itmay be desirable to utilize remotely actuatable valves in place of themanually operated valves 142. A highlow safety valve 144, also mountedon the wellhead 14 outside the satellite body 15, will automaticallyclose should the pressure in the well 138 exceed a specified highpressure or drop below a specified low pressure.

From the upper end of the wellhead 14, the fluid is directed throughconnector unit 54 to the portion of the wellhead equipment within thesatellite body 15 where one or more TFL tools are stored in a storagechamber, designated by block 146. (A TFL storage device and a paraffincutting tool, designed to be stored therewithin, are fully described inthe patent application Ser. No. 579,571 of James T. Dean, entitledStorage System for TFL Tools, filed Sept. 15, 1966, now US. Pat. No.3,396,789. In FIG. 3 of the Dean patent, the incorporation of thedescribed Roiagje device in a fluid circuit for automaticallymaintaining a subset! well is shown.) The TFL storage chamber 146 islocated in the previously described bypass conduit section 124, as is aTFL tool control valve 148, which remains closed except during TFLmaintenance and/or testing. The branch conduit 76 contains a pressureindicator 150, an orifice metertlSZfand a production wing valve 154. Theproduction wing' valve 154 is normally open while the well 138 isproducingand closed during TFL. operations. The branch conduit 76through which the produced fluid generally flows, provides a, patharound the TFL storage chamber 146, and the'closedcontrol valve 148.When the well 138 is producing, the fluids flew from TD'point 136, upthrough the storm choke 140, and the series of valves 142 and 144, ofthe wellhead 14, into the'branch conduit 76. The pressure and flow rateof the fluid. at the wellhead 14 are monitored at alltimes by thepressure indicator 150 and the orifice meter 152, respectively, andrepresentative signals are transmitted to, and recorded within, thecontrol section=66 of the satellite station 10. l

The produced fluid flowing through the branch conduit 76,

past the interconnectionwith the bypass conduit section 124, leaves theportion of the system designated'in the schematic diagram asWellhead andWellhead Equipment and enters the portion designated ProductionSystemthrough a rotary variable choke 156. As the fluid passes throughthevariable choke 156, the pressure is lowered from that'at the wellhead14 to a pressure just above that necessary to drive .the fluid from themarine bottom to the surface. From the rotary choke 156, the producedfluid is directed through a check valve 157 into a collector manifold158. Branch conduits'76',:each having a check valve 157', also shown asleading into the collector manifold 1' 5 8 ,'are connected to thewellhead equipment of the various wells encircling the satellite station10. A pressure sen- .sor 160 is mounted inthe collector manifold 158 tomonitor the pressure ,therewithin, a signal representative of which istransmitted to and recorded within the control portion of the satellitestation 10. The rotary variable choke 156 is controlled in response tothe pressures indicatedby the pressure sensors 150 and 160. Threegravity separators 72 areconnected, in parallel, tothecollectorinanifold 158through inlet lines 162, each having a shutoffvalve 163 therewithin. The liquids, including oil and water, exit forthe most part through lines 98 which empty into a liquid collectormanifold 164. This manifold corresponds to the circular manifold 100shown in FIG. 3. From the liquid collector'manifold164, the oil exitsthrough the 'outlet line 102 and ,is'tran'sferred to storage throughshipping line 18 after passing through a flow meter 166. A clean oiloutlet line 108, as pre vi'ously discussed, extends from a point withineach of the separators 72, from where substantially clean pure oil canbe :obtained, to a manifold 175, which empties in turn into the upstreamend of a line 174 connected at its downstream end to an inlet port of athree-way two-position valve 181) inthe TFL Fluid Supply System. The gasaccumulating in the separators 72 passes out througha high liquidshutoff valve 168 located in the upper end of each of the separators 72, into a gasoutlet line 120, which empties into a gas collectormanifold .170. The major portion of the gas leaves-the-manifold 170through the main gas outlet line 130, passing through an orificemeter172, and is transferred to storage or disposal means. By disposal meansis meant fflaring" or shallow sand injecting as previously discussed.The fluid pressure supply lin'e, 1 191 is connected between the bypassconduit 124; at-one -end,thereof, and a manifold 159 at the other end.Lines '1 19' connect the bypass.

conduits of the other wells, which flow through the satellite station10, with the manifold 159. The inlet-of an auxiliary separator 161,where only a small pressure cut is taken, is in fluid connection withthe manifold 159 through a high pres;

are designed so that any two area" that are required to process thetotal amount of fluid passing through the satellite station 10. With thesame rate'of flow of gas through the oriface meter 172, and liquidthrough the flow meter 166.11 signal warning of an increase in pressurewill be transmitted to the control portion 66 of the satellite station10 from the sensor 160 in the manifold 158, indicating that there is aproblem. Furthermore, the closing of avalve 168 can be made to actuatean electric switch, which in turn will provide a signal indicating whichseparator is malfunctioning. The production stream through the pluggedseparator 72 would then be cutoff by closing the respective shutoffvalve 163 so that the respective separator 72 can be serviced bypersonnel within the satellite station 10. a

The portion of the schematic diagram designated as the TFL Fluid SupplySystem contains a-fluiid storage means 178, which corresponds to theopen-bottomed fluid storage section 70 of the satellite station 10 asshown in FIG. 2. Thestorage means 178 is connected to a first inlet portof the three-way two'position valve. 180 through a line 190 having asalt water sensor 188 therein to provide a signal in the control sectionof the satellite station 10 indicating that the storage means 178 isempty of treating fluid and now contains only salt water. The otherinlet port of the three-way two-position valve 180, as previouslydiscussed, is connected to asource of clean oil through the line 174extending from the manifold 175 in the Production System portion of theschematic diagram. The outlet of the three-way two-position valve isoperatively connected to the inlet of the pump portion of theturbine-pump 112, the outlet of the pump portion of the turbine-pump 112being connected to an inlet of a manifold 182 through a conduit 184 Thepower for driving the. pump portion of the turbine-pump 112 is providedby gas under pressure obtained through the line 118 from the auxiliaryseparator 161 which is outlined. By opening and closing a'valve 176 inthe line 118,

the operation of the turbine-pump 112 may be controlled. From themanifold 182 the clean oil and/or the treating fluid, under pressure, ispumped through one or more of the outlet lines192 at a time, each of theoutlet lines192 having a check valve 194 and a selectively actuatedcutoff valve 196 therein from which the fluid is directed throughtherespective line 122 into the Well and Wellhead Equipment portion of theschematic diagram where it is directed into the bypass conduit 124between the TFL tool storage chamber 146 and the shutoff valve 148.Outletlines 192', each having a one-way check valve 194' and a shutoffvalve 196 therein, are connected to the bypass conduits of the Well andWellhead Equipment portions of the other wells (not shown) producingthrough the respective satellitestation 10. I i

To commence a TFL maintenance and/or testing procedure, valves 148 and154 in the Well and Wellhead Equipment portion would both be closed..The shutoff valve 176, in the TFL Fluid Supply System, connected to theinput I of the turbine-pump ll2would be open to activate the turbinesure line 165. The turbine gas supply line 118is connected between thegas outlet of the auxiliary separator 161 and the inlet of the turbineof the turbine pump 112 of the TFL. Fluid Supply System to supply highpressure gas to thepump portion portion. For paraffin removal, forinstance, a paraffin solvent and corrosion inhibitor stored in thestorage means 178 would first be drawn into the input of the pumpsection of the turbine-pump 112 by the proper positioning of the valve180.

After pumping approximately one barrel of treating fluid through thevalve 180, the position of the valve would be changed so that the oilfrom line 174 would then be supplied to the pump portion of theturbine-pump 112. One or more of the valves 196, 196 would be open topermit the fluid driven by the turbine-pump 112 to exit from the header182 through a line 122 to apply fluid pressure inithe section of thebypass conduit 124, of the Well and Wellhead Equipment portion, betweenthe valve 148 and the storage means 146. With the valve 148 closed, thefluid driven through line 122 into the bypass conduit 124, behind thestorage means 146, will cause a paraffin cutting tool 126 positionedwithin the storage means 146 to be propelled down through the curvedtubing section 56 of the connector unit 54 and down through the wellhead14 of the respective well 138. The piston section of the tool 126 is notcompletely sealed within the tubing of the well 138 in which it moves sothat by the time the tool is down in the well, at the lower end of theparaffin deposition zone, all of the treating fluid is in the well aheadof the tool. When the tool 126 reaches the end of its travel, above thestorm choke 140, the valve 176, in the TFL Fluid Supply System portion,controlling the turbine-pump 112, would be shut causing the turbine-pump112 to cease operation. The shutoff valve 148 in the bypass conduit 124is then opened causing the TFL tool 126 to be returned up the well 138by the fluid being produced, which now is directed into the downstreamportion of the branch conduit 76 through the bypass conduit 124. Whenthe TFL tool 126 has reentered the storage chamber 146, an indication ofthis condition will be given in the control section 66. A switchingmeans for providing this function is shown in the Dean patent US. Pat.No. 3,396,789 discussed above. At this time, the valve 148, in thebypass conduit 124, will be shut and the valve 154, in the branchconduit 76, will be reopened, returning the well to production throughthe branch conduit 76. All of the previously described steps can besequentially performed by an operator'in the control section 66 of thesatellite station 10, by remote control from the floating master station20, or by a programmed computer, or by a combination of theaforementioned methods.

FIG. illustrates a modification in which an electric motor 198 isutilized for driving a pump 200. With the substitution of the electricmotor 198 and the pump 200 for the turbinepump 112 (shown in FIG. 4),the ga's'line 118 is eliminated and the only exit line from the manifold170 is the line 130.

The remainder of the TFL Fluid'Supply System (shown in FIG. 5) isidentical to that shown in FIG. 4, therefore being a storage means 178connected to one inlet of a three-way two position valve 180' through aline 190' having a salt water sensor 188 therein. The other inlet of thethree-way two-position valve 180' is connected to the line 174 as shownin FIG. 4

which is connected at the other end thereof to a clean oil source in theseparators 72. The outlet of thethree-way twoposition valve 180' isoperatively connected to the inlet of the pump 200. The outlet of thepump 200 is in turn connected, through the line 184, to the header 182,as shown in FIG. 4. The identical procedure would be followed with theexception that electrical power would be used to operate the-electricmotor 198 to drive the pump 200.

FIG. 6 shows the modified Production'System to be used with the typicalhigh gasoil ratio high pressure well. This modified Production System isutilized with the Well and Wellhead Equipment portion and TFL FluidSupply System portion of the schematic diagram of FIG. 4. As theproduced fluid is directed from the branch conduit'76 through a variablechoke 156' and a check valve 157, it is collected in a primary manifold202 (generally similar to the-manifold 78 shown in FIG. 2). The producedfluid in the manifold 202, having a high gas content, is now quite colddue to expansion in the choke 156. This cold fluid passes out of themanifold 202 through a line 204 extending through a heat exchanger unit206 (corresponding to the heat exchanger unit 74 of FIG. 2). The fluid,warmed up in theheat exchanger-unit 206, enters a secondary manifold 208from which it is directed into three separators 72. A pressure sensor209 and a temperature probe 238 are located in the secondary manifold208. From-the separators 72' the major part of the produced liquid iscollected in the manifold 164' after which it is removed through a line1,02

having a flow meter 166 therein, the outlet of the flow meter 166 beingconnected to the inlet of a shipping line 18 connecting the satellitestation 10 with a distant storage facility. Again, clean oil is pickedup by lines 108' and is directed through line 174 to the clean oilsupply inlet of the three-way two-position valve, as shown in FIG. 4.The gas exiting from the separators 72, through lines is collected inthe manifold 170' from which it is, in the main, transmitted through aline 210 from the orifice meter 172, through a safety popoff valve 214,to a gas injection well 212, for disposal in shallow sand formations.The gas enters the injection well 212 through the wellhead 216 thereofhaving a high-low fail-safe valve 218 and a manually operated valve 220.There is also a storm choke 222 beneath the marine bottom in theinjection well 212. If the back pressure in the shallow sand formationsbeing used for disposal should rise above a preset limit of the popoffsafety valve 214, the gas will be directed instead through a line 134'to the surface where it will be flared. To heat the cold fluids withinthe heat exchanger unit 206, warm water, at F. to F is obtained from theTD 228 of a water injection well 226 producing through a wellhead 227comprising a manual valve 230 and an automatic setting valve 232, and arotary choke 234 having a pressure differential indicating device 236located thereacross. The warm water flows through the heat exchangerunit 206, past a series of coils 205, in the line 204. From the heatexchanger unit 206, the then cooled water is directed out through line240 into the surrounding water near the marine bottom. The rotary choke234 is operated automatically in response to a temperature signalobtained from the temperature probe 238 previously described as locatedin the primary manifold 208 downstream of the heat exchanger unit 206.As the temperature sensed by the temperature probe 238 decreases, thechoke 234 is opened further. If the temperature indicated reaches aspecified low level, the satellite station 10 is completely shut FIG. 7is a schematic diagram of another modification of the Production Systemof FIG. 4, for a typical medium gas-oil ratio, medium pressure well. Awell is produced in the same manner as in the previous two examplesutilizing the. same type of well and wellhead equipment. In thismodification the fluid, entering the Production System portion through abranch conduit 76, is directed through a one-way valve 241 into a heatexchanger conduit 242 which traverses a heat exchanger unit 244. Theproduced fluid having been produced from a TD of 10,000 feet makes itsfirst pass through the heat exchanger unit 244 at a temperature of 150F. to 170 F. Upon exiting from the heat exchanger unit 244, a pressurecut is taken through a variable choke 245.'The now cold fluids arepassed back through the heat exchanger unit 244 by the traversing heatexchanger conduit 245 to raise the temperature in the expanded fluid toa prescribed minimum to prevent hydrate formation and wax deposition.From the conduit 245 the fluid passes into a collector manifold 246containing a pressure sensor 238 and temperature probe 209'. Incollector manifold 246, the fluid from the heat exchanger conduit iscombined with the pressure cut fluid from the other wells of thesatellite stations through heat exchanger lines 245'. The fluid fromeach well has previously been directed through the heat exchanger unit244, had a pressure cut taken and then been passed back through the heatexchanger unit 244 through separate conduits. The combined fluid in thecollector manifold 246 is directed out through a conduit 247, making afinal pass across the heat exchanger unit 244 into another collectormanifold 248. From the manifold 248, the fluid is divided into separatestreams and directed into separators 72 through lines 249. The remainderof the fluid system is identical to that already discussed with respectto FIG. 4. If the temperature indicated by the temperature probe 209'decreases below a specified value, all the wells of the satellitestation 10 are shut in. I i v g The schematic diagrams of FIGS. 4-47Illustrate examples of systems to be used in specific cases. However,the features the production wells through the ring li ofthe basetemplate 28'. In this embodiment. instead of using cradling arms asillustrated in FIG. 2, the satellitetbody isfheld in the satellite base28 by a central sleeve 250 depending from the lower end of the satellitebody -15 andautomatic spring-loaded latches (not shown) over theupperend of thetwell' conductorv pipe ofthe water well 52. The latches can:bedisabled by ahydraulic pressure appliedthroughthe conduit 25 2extendingbetween a manifold 25d,tforrning a,portion of the framing ofthe base template 28', at the inner end, and a ,quick-disconnectcoupling section 2 56, at thetouterend. The-outer end of the conduit issupported by askeletalframe 2 58to displace the coupling section 256outward of the well conductor pipes 34. The arrangement of the equipmentwithinthe satellitebody 15' is substantially the same asthe arrangernentwithin the satellite body 15 of the earlier discussed embodiment withthe exception of the orientation of the TFL tool 126 and the associatedhydraulic circuitry. in ,thisinstanceathe connector units 54 are notpermanently attached to the satellite body 15 but instead arestabbed-overttubingnipples 26 0 extending vertically out of theupperendof the satellitetbody ,ISuWhen a wellis to be completed -through oneofthe upstandingwell conductor pipes 34, a wellhead 14' is firstmounted onthe respective well conductor pipe 34. Aconnector unit 55 is laterlowered from the surface to make the connection betweenthe wellheadjflandthe satellitebodyjlS. ,Tihecon- ,nectorunit 54' consistsof mount d@tubingtsection Sti'and a venicaltlubricator section 58'. The lower endof thejlubricator section 58' is stabbed over-the tubingtnotshownyextending vertically out of the ripper end of thewellhead-514", .while the outer vertical free ends of the curved tubing section54 stabs over the respective ones of the upstanding [tubing nipples 260extending out of ,the upperendofthe satellite .body lnthis manner, witheach v connector section Sgl' being individually engaged between thewellhead .14 and the respeictivenpstanding tubingnipples 260, greatertolerances can'gbe allowedjn installing the satellitebody l5.Furthermore,an individual ,well can be produced through the satellitestation while the remaining wells are still being drilled and completed.The verticalorientationof the tubing nipples260 extending verticallyinto the satellite body ;l 5' presents no problem, each of the TFLstorage chambersltt 6" is reoriented into;a vertical position so as tobe coaxial with therespectiye-tubing nipples 260. The verticalpositionof the storage chamber 146' permits the TFL tool 126' storedtherewithin ,to move easily into respective tubing nipples .so that itcan be pumped, under fluid pressure, through afull 1, 80 bend in the,tubin gsections 5,6'.of the connector unit 54' .Suchabend, of 180 willnot present any insurmountable problems requiring vonly that the .wellsbe spaced out far enoughfrom the satellite body to obtain a 5-footradius bend in the conduit. Staboverconnections, as discussed in thisapplication, are more -fullydescribed in the Manning applicationSer. No.663,799. Althoughthe present invention has been described in connectionwith details of the specific embodiments thereof, it is to be understoodthat such details are not intended to limit the scope of the invention.The terms and expressions employed are used .in a descriptive and not alimiting senseand there is no intention of excluding such equivalentsin'the invention ,described as fall within the scope of the claims-. Nowhaving described the apparatus and methods herein disclosed, referenceshould be had to the claims which follow.

We claim: j i

1. A system for maintaining a plurality of submerged wells from acentral station comprising: a central station comprising a submergible,watertight shell and having a first manifold therewithin; first conduitmeans providing separate fluid connections between production passagesof each of said plurality of wells and said first manifold, each of saidfirst conduit means having parallel fluid flow paths including a firstflow path for production flow and a second flowpath for inserting wellmaintenance tools intoa respective production passage of the respectivewell; a first shutoff valve insaid first flownpath; means within saidshell, for insertingatool into said respective production passage beingconnected in series in said second flow path; and a second shutoffvalvein said second flow path, said second shutoff valvebeing located betweensaid tool-in serting means and said first manifold.

2. Aisystem for maintaining a;plurality of wells from a central station,as recited in claim 11, comprisingra source of, fluid underpressure forpumping awell maintenancetool fromsaid tool-inserting means into saidrespective production'passage tagainstwell pressure; and second conduitmeans fluidly connecting said source of fluid underpressure with saidsecond flow pathbetween said tool-inserting means and said secondshutoffvalve.

3. A system formaintaining aplurality of wells from a central stationcomprising: a central station having a first manifold .therewithin;first conduit means providing separate fluid connectionsbetween,productionpassages of each of said ,plurality of wells and saidfirst manifold,,each of said first conduit means having parallel fluidflow ,paths includinga first flow path ,for production flowand a secondflow pathfor inserting ,well maintenance tools into a respectiveproduction passage of the respectivewelh a-first shutoff valve in saidfirst flow path; means for inserting a tool into said respectiveproduction ,passage being connected .in series in said second.=.flow,path; a second shutoff valve in said secondflow path, said secondshutoffvalvebeing located between said tool-inserting,rneansandsaidfirst manifold; asource of fluid underpressure for pumping a well maintenance tool from said tool-inserting \means ,intosaid respective production passage against well pressure secondconduitmeansfluidly connecting said source of fluid under pressure withsaid second flow ,path between said-tool-inserting means and said secondshutoff valve; and a pressure-reducing means locatedin each firstconduit just upstream of said first manifold.

Aisystem for-maintainingaplurality of wells froma central station, asrecitedi in claim 3, comprising: a source of fluid under pressure forpumping a tool from said tool-inserting means into said respectiveproduction passage against well pressure; second conduit meansforconnectingsaid source of fluid under pressure with said second flow pathbetween said tool-inserting means and said second shutoff valve; saidsource of fluid under pressure :being a turbine-pump; a third conduitconnected into said first conduit upstream of said pressurereducingmeans in at least one of saidsecond flow paths for supplying gas underpressure from said] at least one second flow path to the turbine portionof said turbine-pump; and means for exhausting waste gas from saidturbine portion of said turbine-pump.

5. Asystem for maintaining a plurality of wells froma central station,as recited in claim 4, wherein there is means for disposing of waste gasthat has been used to drive said turbine portion ,of said turbine-pump;said waste gas disposal means including a fourth conduit fluidlyconnecting the outletof said turbine portion of said turbine-pump with agas manifold downstream of said pressure-reducing means downstream ofsaidfirst manifold, inlets of a plurality of separators connected inparallel to outlets of said first manifold; gas outlets of saidplurality of separators connected in parallel to said gas manifold; anda gas outlet line connected to an outlet of said gas manifold fordirecting the separated-out produced gas from said central station.

6. A system for maintaining a plurality of wells from a central station,as recited in claim 4, wherein said third conduit means includes firstand second fluid lines and an auxiliary of said first fluid line of saidthird conduit means; and said second fluid line of said third conduitmeans being connected between a gas outlet of said auxiliary separatorand an inlet to said turbine portion of said turbine-pump.

7. A system for maintaining a plurality of wells from a central station,as recited in claim 6. wherein said inlet of said auxiliary separator isfluidly connected to an outlet of a third manifold by a third fluid lineof said third conduit means; and a first portion of said second fluidline of said third conduit means is fluidly connected to each of saidsecond flow paths of said plurality of wells of said central station toinlets of said second manifold.

8. A system for maintaining a plurality of wells from a central station,as recited in claim 3, comprising: a power-driven pump for supplyingfluid under pressure for pumping a tool from said tool-inserting meansinto said respective production passage against well pressure; andsecond conduit means for operatively connecting an outlet of said pumpwith said second flow path between said tool-inserting means and saidsecond shutoff valve, said pressure-reducing means being located betweensaid second shutoff valve and said first manifold.

9. A system for maintaining a plurality of wells from a central station,as recited in claim 8, wherein a means for driving said power-drivenpump is an electric motor.

10. A system for maintaining a plurality of wells from a centralstation, as recited in claim 8, wherein there is means for selectivelyconnecting the inlet of said power-driven pump to either a source ofwell treating fluid or a source of substantially clean, dead oil.

1]. A system for maintaining a plurality of wells from a centralstation, as recited in claim 8, wherein there is a three-waytwo-position valve, the outlet port of said three-way two-position valvebeing connected to the inlet of said power-driven pump; a first inletport of said three-way two-position valve being connected to a source ofwell treating fluid; and a second inlet port of said three-waytwo-position valve being connected to a source of substantially clean,dead oil.

12. A system for maintaining a plurality of wells from a centralstation, as recited in claim 8, wherein said second conduit meanscomprises: first and second fluid lines and a second manifold; saidfirst fluid line of said second conduit means being connected betweenthe outlet of said power-driven pump and an inlet of said secondmanifold, a plurality of second fluid lines of said second conduit meansbeing connected between outlets of said second manifold and each of saidplurality of second flow paths.

13. A system for maintaining a plurality of wells from a centralstation, as recited in claim 12 wherein there is a shutoff valve in eachof said second fluid lines of said second conduit means.

14. A system for maintaining a plurality of wells from a centralstation, as recited in claim 8, wherein there is a source ofsubstantially clean, dead oil; fifth conduit means for fluidlyconnecting said source of substantially clean, dead oil to an inlet ofsaid power-driven pump.

15. A system for maintaining a plurality of wells from a centralstation, as recited in claim 14, wherein said source of substantiallyclean, dead oil is at least one separator means for fluidly connectingan inlet of said at least one separator with an outlet of said firstmanifold, said separator comprising: a first outlet for separated-outgas; a second outlet, at the lower end of said separator, for aseparated-out mixture of fluids and solids in suspension therein; and athird outlet, above said second outlet, for separated-out substantiallyclean, dead oil.

16. A system for maintaining a plurality of wells from a centralstation, as recited in claim 3, wherein there are a plurality ofseparators fluidly connected in parallel with said first manifold; afourth manifold for collecting produced gas; means for fluidlyconnecting gas outlets of said plurality of separators in parallel withsaid fourth manifold; a gas outlet line for directing produced gas fromsaid fourth manifold and out of said'central station; a fifth manifoldfor collecting produced liquids; means for fluidly connecting liquidsoutlets of said plurality of separators in parallel with said fifthmanifold; and a liquids outlet line for direction produced liquids fromsaid fifth manifold and out of central station.

17. A system for maintaining a plurality of wells from a centralstation, as recited in claim 16, wherein there is a sixth manifold forcollection clean, dead oil; means for fluidly connecting clean, dead oiloutlets of said plurality of separators, above said liquids outlets ofsaid respective separators, in parallel with said sixth manifold forsupplying clean, dead oil for pumping well maintenance tools into theproduction passages of said respective wells.

18. A system for maintaining a plurality of wells from a centralstation, as recited in claim 16, wherein said gas outlet line,downstream of said fourth manifold, is in fluid connection with a meansfor injecting gas into at least one underground formation.

19. A system for maintaining a plurality of wells from a centralstation, as recited in claim 18, wherein said at least one undergroundformation is an underground formation from which fluids are beingproduced through at least one of said wells whereby said undergroundformation can be repressurized.

20. A system for maintaining a plurality of wells from a centralstation, as recited in claim 18, wherein said at least one undergroundformation is a shallow, low pressure porous formation, not beingproduced, whereby waste gas can be disposed of.

21. A system for maintaining a plurality of wells from a centralstation, as recited in claim 3, wherein each of said pressure-reducingmeans is a choke whereby the produced fluid is expanded downstream ofeach of said chokes; and means for heating the expanded fluid justdownstream of said chokes to hinder the formation of hydrates andemulsions and to prevent the deposition of paraffin in the equipment.

22. A system for maintaining a plurality of wells from a centralstation, as recited in claim 21, wherein the source of heat for saidheating means is outside of said produced fluid.

23. A system for maintaining a plurality of wells from a centralstation, as recited in claim 22, wherein said heating means is anindirect heat exchanger unit; a first fluid line portion of each of saidfirst conduit means, upstream of said chokes, for directing the producedfluid, under pressure, in a first pass through said indirect heatexchanger unit; and a second fluid line portion of each of said firstconduit means, between the respective choke, and said first manifold,for directing the produced fluid, now expanded, in a second pass throughsaid heat exchanger unit whereby heat is exchanged between said firstand said second passes to warm the expanded fluids downstream of saidchokes.

24. A system for maintaining a plurality of wells from a centralstation, as recited in claim 23, wherein there is a third pass throughsaid heat exchanger unit fluidly connected at the upstream end to thesingle outlet of said first manifold.

25. A system for maintaining a plurality of wells from a centralstation, as recited in claim 24, wherein the downstream end of saidthird pass through said heat exchanger is in fluid connection with aseventh manifold; and means for fluidly connecting each of a pluralityof separators in parallel with said seventh manifold.

26. A method for maintaining a well in conjunction with a wellmaintenance tool that can be pumped into a production passage of saidwell, said production passage of said well being a fluid connection withequipment in a distant production facility through a first conduitmeans; said first conduit means having parallel fluid paths includingafirst path connected to a first manifold for production flow and asecond path for insert ing said well maintenance tool into a respectiveproduction passage of a respective well; a first shutoff valve in saidfirst flow path; a tool storage means being connected in series in saidsecond flow path; a second shutoff valve in said second flow path, saidsecond shutoff valve being located between said tool storage means andsaid first manifold; a source of clean, dead oil for pumping said wellmaintenance tool down said respective well production passage againstwell pressure; a source of well treating fluid; and means forselectively fluidly connecting a second conduit means between saidsource of clean, dead oil and said second flow path between said toolstorage means and said second shutoff valve, said selective connectingmeans is operable to selectively alternately connect said second conduitto said source of clean, dead oil or to said source of well treatingfluid, including the following steps:

a. shutting said first shutoff valve while leaving said second shutoffvalve closed as it is positioned during production of fluid from saidrespective production passage;

. selectively fluidly connecting said source of well treating fluid withsaid second conduit means;

. pumping a prescribed amount of well treating fluid behind said wellmaintenance tool;

d. selectively fluidly connecting said source of clean, dead oil withsaid second flow path through said second conduit means; and

e. pumping clean, dead oil from said source through said second conduitmeans whereby a well maintenance tool in said storage means is pumpedout of said storage means and down through said production passage ofsaid respective well.

27. A method for maintaining a well in conjunction with a wellmaintenance tool that can be pumped into a production passage of a well,as recited in claim 26, wherein said well treating fluid is a paraffindissolving agent and said well maintenance tool is a paraffin scrapingtool.

28. A method for maintaining a well in conjunction with a wellmaintenance tool that can be pumped into a production passage of a well,as recited in claim 26, including the following additional steps to beperformed for the retrieval of said well maintenance tool from saidproduction passage by the pressure of fluids being produced through saidwell:

f. shutting off the supply of fluid under pressure through said secondconduit;

g. opening said second shutoff valve so that well fluids are producedthrough said second flow path;

h. closing said second shutoff. valve when said well maintenance toolhas been driven up said production passage and into said storage meansby the produced fluids; and

i. opening said first shutoff valve after said well maintenance tool isagain within said storage means whereby well production continuesthereafter through said first flow path of said first conduit into saidproduction facility.

29. A method for maintaining a well in conjunction with a wellmaintenance tool that can be pumped into a production passage of a well,as recited in claim 26, including the following additional steps:

j separating the produced fluids into liquid and gaseous components;

k. drawing off clean, dead oil from the upper portion of said liquidcomponent which could include oil, water, and/or solids; and

l. directing said clean, dead oil to the inlet of a power-driven pump,the outlet of said power-driven pump being connected to said secondconduit means.

30. A method for maintaining a well in conjunction with a wellmaintenance tool that can be pumped into a production passage ofa well,as recited in claim 26, wherein the means for pumping said oil is agas'driven turbine-pump, including the following additional steps:

m. separating the produced fluid into liquid and gaseous components;

n. drawing off at least a portion of the gaseous component;

and

o. directing said gaseous component, drawn off, into the inlet of theturbine portion of said turbine-pump to drive the turbine.

31. A method for maintaining a well in conjunction with a wellmaintenance tool that can be pumped into a production passage of a well,as recitedin claim 26, whe rein th re are a plurality of wells spacedfrom said production facilityQsaid production facility being a satellitestation located in the field being exploited, including the followingadditional step:

p. collecting the produced fluids from said plurality of wells in afirst manifold.

32. A method for maintaining a well in conjunction with a wellmaintenance tool that can be pumped into production passage of a well,as recited in claim 31, including the following additional step:

q. choking the flow of produced fluid in the first conduit means justprior to the collecting of said produced fluids in said first manifoldwhereby the pressure in said produced fluids is reduced in said firstmanifold.

33. A method for maintaining a well in conjunction with a wellmaintenance tool that can be pumped into a production passage of a well,as recited in claim 32, including the following additional step: t

r. heating said produced fluids subsequent to reducing the pressurethereof by choking the flow of said produced fluids.

@fifi UFHTED STATES PATENT OFFHHE CERTIFICATE OF CORRECTION Patent No.3,556,218 Dated January 19, 1971 Invenuns) William A. Talley, Jr. andJames T. Dean It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 51, -a--has been omitted before "stabover".

Column 16, Claim 16, line 3, "direction" should be "directing line 4,--said-- has been omitted before "central".

Claim 17, line 7, "collection" should be --collect:

Claim 26, line 66, before "fluid" "a" should be ca1 and --in--inserted.

Column 18, Claim 32, line 33, --a-- has been omitted before"production".

Signed and sealed this 25th day of May 1971.

(SEAL) Attest:

EDWARD M.FLETCH5R,JR. WILLIAM E. SCHUYLER, JR. Attesting OfficerCommissioner of Patents

1. A system for maintaining a plurality of submerged wells from acentral station comprising: a central station comprising a submergible,watertight shell and having a first manifold therewithin; first conduitmeans providing separate fluid connections between production passagesof each of said plurality of wells and said first manifold, each of saidfirst conduit means having parallel fluid flow paths including a firstflow path for production flow and a second flow path for inserting wellmaintenance tools into a respective production passage of the respectivewell; a first shutoff valve in said first flow path; means within saidshell for inserting a tool into said respective production passage beingconnected in series in said second flow path; and a second shutoff valvein said second flow path, said second shutoff valve being locatedbetween said toolinserting means and said first manifold.
 2. A systemfor maintaining a plurality of wells from a central station, as recitedin claim 1, comprising: a source of fluid under pressure for pumping awell maintenance tool froM said tool-inserting means into saidrespective production passage against well pressure; and second conduitmeans fluidly connecting said source of fluid under pressure with saidsecond flow path between said tool-inserting means and said secondshutoff valve.
 3. A system for maintaining a plurality of wells from acentral station comprising: a central station having a first manifoldtherewithin; first conduit means providing separate fluid connectionsbetween production passages of each of said plurality of wells and saidfirst manifold, each of said first conduit means having parallel fluidflow paths including a first flow path for production flow and a secondflow path for inserting well maintenance tools into a respectiveproduction passage of the respective well; a first shutoff valve in saidfirst flow path; means for inserting a tool into said respectiveproduction passage being connected in series in said second flow path; asecond shutoff valve in said second flow path, said second shutoff valvebeing located between said tool-inserting means and said first manifold;a source of fluid under pressure for pumping a well maintenance toolfrom said tool-inserting means into said respective production passageagainst well pressure; second conduit means fluidly connecting saidsource of fluid under pressure with said second flow path between saidtool-inserting means and said second shutoff valve; and apressure-reducing means located in each first conduit just upstream ofsaid first manifold.
 4. A system for maintaining a plurality of wellsfrom a central station, as recited in claim 3, comprising: a source offluid under pressure for pumping a tool from said tool-inserting meansinto said respective production passage against well pressure; secondconduit means for connecting said source of fluid under pressure withsaid second flow path between said tool-inserting means and said secondshutoff valve; said source of fluid under pressure being a turbine-pump;a third conduit connected into said first conduit upstream of saidpressure-reducing means in at least one of said second flow forsupplying gas under pressure from said at least one second flow path tothe turbine portion of said turbine-pump; and means for exhausting wastegas from said turbine portion of said turbine-pump.
 5. A system formaintaining a plurality of wells from a central station, as recited inclaim 4, wherein there is means for disposing of waste gas that has beenused to drive said turbine portion of said turbine-pump; said waste gasdisposal means including a fourth conduit fluidly connecting the outletof said turbine portion of said turbine-pump with a gas manifolddownstream of said pressure-reducing means downstream of said firstmanifold, inlets of a plurality of separators connected in parallel tooutlets of said first manifold; gas outlets of said plurality ofseparators connected in parallel to said gas manifold; and a gas outletline connected to an outlet of said gas manifold for directing theseparated-out produced gas from said central station.
 6. A system formaintaining a plurality of wells from a central station, as recited inclaim 4, wherein said third conduit means includes first and secondfluid lines and an auxiliary separator, an inlet of said auxiliaryseparator being operatively fluidly connected to an outlet of said firstfluid line of said third conduit means; and said second fluid line ofsaid third conduit means being connected between a gas outlet of saidauxiliary separator and an inlet to said turbine portion of said turbineportion of said turbine-pump.
 7. A system for maintaining a plurality ofwells from a central station, as recited in claim 6, wherein said inletof said auxiliary separator is fluidly connected to an outlet of a thirdmanifold by a third fluid line of said third conduit means; and a firstportion of said second fluid line of said third conduit means is fluidlyconnected to each of said second flow paths of said plurality of wellsof said central station to inlets of said second manifold.
 8. A systemfor maintaining a plurality of wells from a central station, as recitedin claim 3, comprising: a power-driven pump for supplying fluid underpressure for pumping a tool from said tool-inserting means into saidrespective production passage against well pressure; and second conduitmeans for operatively connecting an outlet of said pump with said secondflow path between said tool-inserting means and said second shutoffvalve, said pressure-reducing means being located between said secondshutoff valve and said first manifold.
 9. A system for maintaining aplurality of wells from a central station, as recited in claim 8,wherein a means for driving said power-driven pump is an electric motor.10. A system for maintaining a plurality of wells from a centralstation, as recited in claim 8, wherein there is means for selectivelyconnecting the inlet of said power-driven pump to either a source ofwell treating fluid or a source of substantially clean, dead oil.
 11. Asystem for maintaining a plurality of wells from a central station, asrecited in claim 8, wherein there is a three-way two-position valve, theoutlet port of said three-way two-position valve being connected to theinlet of said power-driven pump; a first inlet port of said three-waytwo-position valve being connected to a source of well treating fluid;and a second inlet port of said three-way two-position valve beingconnected to a source of substantially clean, dead oil.
 12. A system formaintaining a plurality of wells from a central station, as recited inclaim 8, wherein said second conduit means comprises: first and secondfluid lines and a second manifold; said first fluid line of said secondconduit means being connected between the outlet of said power-drivenpump and an inlet of said second manifold, a plurality of second fluidlines of said second conduit means being connected between outlets ofsaid second manifold and each of said plurality of second flow paths.13. A system for maintaining a plurality of wells from a centralstation, as recited in claim 12 , wherein there is a shutoff valve ineach of said second fluid lines of said second conduit means.
 14. Asystem for maintaining a plurality of wells from a central station, asrecited in claim 8, wherein there is a source of substantially clean,dead oil; fifth conduit means for fluidly connecting said source ofsubstantially clean, dead oil to an inlet of said power-driven pump. 15.A system for maintaining a plurality of wells from a central station, asrecited in claim 14, wherein said source of substantially clean, deadoil is at least one separator means for fluidly connecting an inlet ofsaid at least one separator with an outlet of said first manifold, saidseparator comprising: a first outlet for separated-out gas; a secondoutlet, at the lower end of said separator, for a separated-out mixtureof fluids and solids in suspension therein; and a third outlet, abovesaid second outlet, for separated-out substantially clean, dead oil. 16.A system for maintaining a plurality of wells from a central station, asrecited in claim 3, wherein there are a plurality of separators fluidlyconnected in parallel with said first manifold; a fourth manifold forcollecting produced gas; means for fluidly connecting gas outlets ofsaid plurality of separators in parallel with said fourth manifold; agas outlet line for directing produced gas from said fourth manifold andout of said central station; a fifth manifold for collecting producedliquids; means for fluidly connecting liquids outlets of said pluralityof separators in parallel with said fifth manifold; and a liquids outletline for direction produced liquids from said fifth manifold and out ofcentral station.
 17. A system for maintaining a plurality of wells froma central station, as recited in claim 16, wherein there is a sixthmanifold for collection clean, dead oil; means for fluidly connectingclean, dead oil outlets of said plurality of separators, above saidliquids outlets of said respective separators, in parallel with saidsixth manifold for supplying clean, dead oil for pumping wellmaintenance tools into the production passages of said respective wells.18. A system for maintaining a plurality of wells from a centralstation, as recited in claim 16, wherein said gas outlet line,downstream of said fourth manifold, is in fluid connection with a meansfor injecting gas into at least one underground formation.
 19. A systemfor maintaining a plurality of wells from a central station, as recitedin claim 18, wherein said at least one underground formation is anunderground formation from which fluids are being produced through atleast one of said wells whereby said underground formation can berepressurized.
 20. A system for maintaining a plurality of wells from acentral station, as recited in claim 18, wherein said at least oneunderground formation is a shallow, low pressure porous formation, notbeing produced, whereby waste gas can be disposed of.
 21. A system formaintaining a plurality of wells from a central station, as recited inclaim 3, wherein each of said pressure-reducing means is a choke wherebythe produced fluid is expanded downstream of each of said chokes; andmeans for heating the expanded fluid just downstream of said chokes tohinder the formation of hydrates and emulsions and to prevent thedeposition of paraffin in the equipment.
 22. A system for maintaining aplurality of wells from a central station, as recited in claim 21,wherein the source of heat for said heating means is outside of saidproduced fluid.
 23. A system for maintaining a plurality of wells from acentral station, as recited in claim 22, wherein said heating means isan indirect heat exchanger unit; a first fluid line portion of each ofsaid first conduit means, upstream of said chokes, for directing theproduced fluid, under pressure, in a first pass through said indirectheat exchanger unit; and a second fluid line portion of each of saidfirst conduit means, between the respective choke, and said firstmanifold, for directing the produced fluid, now expanded, in a secondpass through said heat exchanger unit whereby heat is exchanged betweensaid first and said second passes to warm the expanded fluids downstreamof said chokes.
 24. A system for maintaining a plurality of wells from acentral station, as recited in claim 23, wherein there is a third passthrough said heat exchanger unit fluidly connected at the upstream endto the single outlet of said first manifold.
 25. A system formaintaining a plurality of wells from a central station, as recited inclaim 24, wherein the downstream end of said third pass through saidheat exchanger is in fluid connection with a seventh manifold; and meansfor fluidly connecting each of a plurality of separators in parallelwith said seventh manifold.
 26. A method for maintaining a well inconjunction with a well maintenance tool that can be pumped into aproduction passage of said well, said production passage of said wellbeing a fluid connection with equipment in a distant production facilitythrough a first conduit means; said first conduit means having parallelfluid paths including a first path connected to a first manifold forproduction flow and a second path for inserting said well maintenancetool into a respective production passage of a respective well; a firstshutoff valve in said first flow path; a tool storage means beingconnected in series in said second flow path; a second shutoff valve insaid second flow path, said second shutoff valve being located betweensaid tool storage means and said first manifold; a source of clean, deadoil for pumping said well maintenance tool down said respective wellproduction passage against well pressure; a source of well treatingfluid; and means for selectively fluidly connecting a second conduitmeans between said source of clean, dead oil and said second flow pathbetween said tool storage means and said second shutoff valve, saidselective connecting means is operable to selectively alternatelyconnect said second conduit to said source of clean, dead oil or to saidsource of well treating fluid, including the following steps: a.shutting said first shutoff valve while leaving said second shutoffvalve closed as it is positioned during production of fluid from saidrespective production passage; b. selectively fluidly connecting saidsource of well treating fluid with said second conduit means; c. pumpinga prescribed amount of well treating fluid behind said well maintenancetool; d. selectively fluidly connecting said source of clean, dead oilwith said second flow path through said second conduit means; and e.pumping clean, dead oil from said source through said second conduitmeans whereby a well maintenance tool in said storage means is pumpedout of said storage means and down through said production passage ofsaid respective well.
 27. A method for maintaining a well in conjunctionwith a well maintenance tool that can be pumped into a productionpassage of a well, as recited in claim 26, wherein said well treatingfluid is a paraffin dissolving agent and said well maintenance tool is aparaffin scraping tool.
 28. A method for maintaining a well inconjunction with a well maintenance tool that can be pumped into aproduction passage of a well, as recited in claim 26, including thefollowing additional steps to be performed for the retrieval of saidwell maintenance tool from said production passage by the pressure offluids being produced through said well: f. shutting off the supply offluid under pressure through said second conduit; g. opening said secondshutoff valve so that well fluids are produced through said second flowpath; h. closing said second shutoff valve when said well maintenancetool has been driven up said production passage and into said storagemeans by the produced fluids; and i. opening said first shutoff valveafter said well maintenance tool is again within said storage meanswhereby well production continues thereafter through said first flowpath of said first conduit into said production facility.
 29. A methodfor maintaining a well in conjunction with a well maintenance tool thatcan be pumped into a production passage of a well, as recited in claim26, including the following additional steps: j. separating the producedfluids into liquid and gaseous components; k. drawing off clean, deadoil from the upper portion of said liquid component which could includeoil, water, and/or solids; and l. directing said clean, dead oil to theinlet of a power-driven pump, the outlet of said power-driven pump beingconnected to said second conduit means.
 30. A method for maintaining awell in conjunction with a well maintenance tool that can be pumped intoa production passage of a well, as recited in claim 26, wherein themeans for pumping said oil is a gas-driven turbine-pump, including thefollowing additional steps: m. separating the produced fluid into liquidand gaseous components; n. drawing off at least a portion of the gaseouscomponent; and o. directing said gaseous component, drawn off, into theinlet of the turbine portion of said turbine-pump to drive the turbine.31. A method for maintaining a well in conjunction with a wellmaintenance tool that can be pumped into a production passage of a well,as recited in claim 26, wherein there are a plurality of wells spacedfrom said production facility, said production facility being asatellite station located in the field being exploited, including thefollowing additional step: p. collecting the produced fluids from saidplurality of wells in a first manifold.
 32. A method for maintaining awell in conjunction with a well maintenance tool that can be pumped intoproduction passage of a well, as recited in claim 31, iNcluding thefollowing additional step: q. choking the flow of produced fluid in thefirst conduit means just prior to the collecting of said produced fluidsin said first manifold whereby the pressure in said produced fluids isreduced in said first manifold.
 33. A method for maintaining a well inconjunction with a well maintenance tool that can be pumped into aproduction passage of a well, as recited in claim 32, including thefollowing additional step: r. heating said produced fluids subsequent toreducing the pressure thereof by choking the flow of said producedfluids.